Can anyone explain the LeChatelier's principle?

Question

I know what it is,,, its just that I really don't understand it.

"If a change is made to a system in chemical equilibrium, the equilibrium shifts to oppose the change until a new equilibrium is reached"

thanks.

Answer 1

First you need a clear idea what equilibrium means in chemical reactions.Here is a good web site http://www.shodor.org/UNChem/advanced/equ/index.html
or check your book.
Since the concentration molecules in the reaction are kept constant by the balance of forward and backward reactions, any external change in the system will change the balance by changing the ratio of the reaction rates.LeChatelier's principle says a new equilibrium will be reached with the ratio of the forward and backward rates changed in the direction that will decrease X if you increase X externally etc.
When dealing with gases remember that PV=NKT

Answer 2

If you have a system which is already in equilibrium then a change it made, the system will correct itself so it will once again reach equilibrium.

Answer 3

That's chemistry, not physics.